src/msw/dcmemory.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dcmemory.cpp
   3 // Purpose:     wxMemoryDC class
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart and Markus Holzem
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21     #pragma implementation "dcmemory.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #ifndef WX_PRECOMP
  32     #include "wx/utils.h"
  33     #include "wx/log.h"
  34 #endif
  35
  36 #include "wx/msw/private.h"
  37
  38 #include "wx/dcmemory.h"
  39
  40 // ----------------------------------------------------------------------------
  41 // wxWin macros
  42 // ----------------------------------------------------------------------------
  43
  44     IMPLEMENT_DYNAMIC_CLASS(wxMemoryDC, wxDC)
  45
  46 // ============================================================================
  47 // implementation
  48 // ============================================================================
  49
  50 // ----------------------------------------------------------------------------
  51 // wxMemoryDC
  52 // ----------------------------------------------------------------------------
  53
  54 wxMemoryDC::wxMemoryDC()
  55 {
  56     m_hDC = (WXHDC) ::CreateCompatibleDC((HDC) NULL);
  57     m_ok = (m_hDC != 0);
  58     m_bOwnsDC = TRUE;
  59
  60     SetBrush(*wxWHITE_BRUSH);
  61     SetPen(*wxBLACK_PEN);
  62
  63     // the background mode is only used for text background and is set in
  64     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  65     ::SetBkMode( GetHdc(), TRANSPARENT );
  66 }
  67
  68 wxMemoryDC::wxMemoryDC(wxDC *old_dc)
  69 {
  70     old_dc->BeginDrawing();
  71
  72     m_hDC = (WXHDC) ::CreateCompatibleDC(GetHdcOf(*old_dc));
  73     m_ok = (m_hDC != 0);
  74
  75     old_dc->EndDrawing();
  76
  77     SetBrush(*wxWHITE_BRUSH);
  78     SetPen(*wxBLACK_PEN);
  79
  80     // the background mode is only used for text background and is set in
  81     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT
  82     ::SetBkMode( GetHdc(), TRANSPARENT );
  83 }
  84
  85 wxMemoryDC::~wxMemoryDC()
  86 {
  87 }
  88
  89 void wxMemoryDC::SelectObject(const wxBitmap& bitmap)
  90 {
  91     // select old bitmap out of the device context
  92     if ( m_oldBitmap )
  93     {
  94         ::SelectObject(GetHdc(), (HBITMAP) m_oldBitmap);
  95         if ( m_selectedBitmap.Ok() )
  96         {
  97             m_selectedBitmap.SetSelectedInto(NULL);
  98             m_selectedBitmap = wxNullBitmap;
  99         }
 100     }
 101
 102     // check for whether the bitmap is already selected into a device context
 103     wxCHECK_RET( !bitmap.GetSelectedInto() ||
 104                  (bitmap.GetSelectedInto() == this),
 105                  wxT("Bitmap is selected in another wxMemoryDC, delete the "
 106                      "first wxMemoryDC or use SelectObject(NULL)") );
 107
 108     m_selectedBitmap = bitmap;
 109     WXHBITMAP hBmp = m_selectedBitmap.GetHBITMAP();
 110     if ( !hBmp )
 111         return;
 112
 113     m_selectedBitmap.SetSelectedInto(this);
 114     hBmp = (WXHBITMAP)::SelectObject(GetHdc(), (HBITMAP)hBmp);
 115
 116     if ( !hBmp )
 117     {
 118         wxLogLastError("SelectObject(memDC, bitmap)");
 119
 120         wxFAIL_MSG(wxT("Couldn't select a bitmap into wxMemoryDC"));
 121     }
 122     else if ( !m_oldBitmap )
 123     {
 124         m_oldBitmap = hBmp;
 125     }
 126 }
 127
 128 void wxMemoryDC::DoGetSize(int *width, int *height) const
 129 {
 130     if ( m_selectedBitmap.Ok() )
 131     {
 132         *width = m_selectedBitmap.GetWidth();
 133         *height = m_selectedBitmap.GetHeight();
 134     }
 135     else
 136     {
 137         *width = 0;
 138         *height = 0;
 139     }
 140 }
 141